●问：The mummy is that of Shepenmut who was once  a singer in the Temple of Thebes.

     ☆答；that代表the mummy。英语that的这个用法，使得在同一句中不必重复mummy这个单词，而英语行文有时是这样避免重复的。
--------------------------------------------------------------------------------

     ●问：在下面这句话里，斜体的that指的是什么？
    Only  first she had to get towels and soap for father and clean things for him to put on ,because he always gets so messed up with  fishing ,and that kept mother busy for a while, that and helping the girls get ready.

     ☆答：指she had to get towels  and soap for father and clean things for him to put on,全句的含义是说：作者的父亲钓鱼经常会把浑身弄得很脏，母亲先得忙着把毛巾，肥皂和父亲的换洗衣服找出来，除此之外，还要帮女儿打扮，为这两桩事她忙了一阵。
   说话的人说到that kept mother busy for a while之后 ,又想起helping the girls get ready ,也占了她的时间，所以重复了that，再加上helping the girls ready,这种文体是口语式的。正式的书面语不会这样写。